1. Field of the Invention
The present invention relates to the field of automatic valves, and more particularly to the field of valves for use in automatic sprinkler systems.
2. Prior Art
Automatic sprinkler systems of various kinds are well known in the prior art, such as by way of example those disclosed in U.S. Pat. Nos. 3,821,967; 3,989,066; 4,107,546; 4,108 419; and 4,114,647. While these sprinkler systems operate in different ways, in general they have the capability of being set to turn on in selected intervals, to remain on for selected durations of time, and in various ways to control more than one valve. Other features such as moisture probes and the like are also known in these prior art systems. Such systems are highly versatile, giving a high degree of control to the user, which control may be changed from time to time at the convenience of the user to accommodate weather changes, seasonal changes, etc. Having a high degree of versatility and control however, can bring with it some degree of complication, both from a design and manufacturing standpoint, and from a user standpoint, with the result that the cost may be somewhat higher than necessary and at least the most unsophisticated users may become confused in attempting to set a system having a full range of choices of parameters for the user to control. This is particularly true for systems wherein settings are made to which the system does not respond to immediately, but rather will respond to at the prescribed times, whereby the user will not immediately get a sense of security that the system is properly set by the immediate response thereof. Further, each control or selection, such as time of day, on time, on/off override, etc., has heretofore generally been a separate manually operable switch, with each switch providing the opportunity for moisture entry and thus premature failure from that cause. Thus, among the objects of the present invention is to minimize the number and complexity of the controls required for the setting of the system, and to provide an immediate response to the user's programming commands so as to give even the most unsophisticated user a real sense of security that the programming has been accomplished properly
Prior art systems also frequently include a way of controlling the turn on and turn off of a valve or overall system in a manner that will not interfere with a preprogrammed watering sequence. For instance, each controller of the fluid control system of U.S. Pat. Nos. 3,821,967 and 3,989,066 included an on switch as well as an off switch which could be used to trigger the respective valve on or off. Such controls are convenient to allow manually causing an extra operating cycle when desired, or alternatively cut short the usual operating cycle. However, since such controls utilize at least in part the batteries, the electronic control circuits, the latching actuator, etc., such controls are themselves dependent upon the proper operation of the entire system. As such, the controls cannot be used in the event of a dead battery to manually operate the system until the battery is replaced, or similarly, in the event the valve fails to automatically turn off due to some failure in the actuator or a relevant portion of the electronics, the same cannot be used as part of the manually operable turn off system to shut off the valve to prevent water damage, etc. It is thus one of the purposes of the present invention to provide a manual turn on and turn off capability which directly manually operates the pilot valve portion of the valve without dependence upon the proper operation of any of the electronics and/or the actuator. Finally, it is also an object of the present invention to seal the actuator region of the valve in a manner isolating the seal from any water filled region of the valve so that the actuator seal is not statically subjected to the high pressure in the valve, or subjected to the dynamic water hammer effect of the valve. Such an isolation avoids any actuator corrosion and premature failure due to an otherwise insignificant leakage of water from the valve assembly due to these static and dynamic effects.